<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>2-相对-绝对-固定默认层级关系</title>
		<style type="text/css">
			div{
				width:200px;
				height:200px;
			}
			.red{
				background:red;
				position: relative;
				left: 0;
				top:0;
			}
			.orange{
				background: orange;
				position: absolute;
				left:30px;
				top:30px;
				z-index: 90;
			}
			.blue{
				background: blue;
				position: fixed;
				left: 60px;
				top: 60px;
				/*层级设置*/
				z-index: 100;
			}
		</style>
	</head>
	<body>
		<div class="red"></div>
		<div class="blue"></div>
		<div class="orange"></div>
	</body>
</html>
